Unsafe Water Sources Research Articles

English

Relatively few studies have explored how resilience of water, sanitation and hygiene (WASH) systems to hazards can be enhanced under the current and future development and climatic challenges pressures in urban areas. This study employed the citizen science approach to build the capacity of citizens and integrate communities into scientific research on water quality and WASH related risk monitoring. Data was collected with assistance of 8 self-motivated and trained citizen science research counterparts. Standard sampling procedures were used to collect water samples from a total of 27 unsafe water sources in Karonga Town. The water samples were analysed for biological, physical and chemical parameters using standard methods. Personal observations were done to determine major sanitary risks impacting on a water sources in the town. It was observed that water from the majority of water samples collected from shallow wells, rivers/streams, lake and boreholes were highly contaminated with Escherichia coli, which were considerably higher than Malawi Bureau of Standards water quality specifications for drinking water. In general, the water is of low mineralization with rock-water interactions and surface pollution from anthropogenic activities such as agricultural activities and municipal wastes being responsible for input of biological, chemical and physical pollutants especially into the unlined and uncovered water sources. The results of the water quality index (WQI) and water quality (WQ) ratings indicated that water is not suitable for direct human consumption prior to treatment. It is recommended that onsite treatment and point of use water treatment interventions should be instituted and advocated to improve human health, livelihoods and to build resilience to WASH related risks and hazards in Karonga Town. Key words: Citizen Science, resilience, urban risks, water quality index, water, sanitation, hygiene.

Impact of extreme climate events on water supply sustainability in Egypt: case studies in Alexandria region and Upper Egypt

Water resources in Egypt have become stressed due to changes in climate patterns. Egypt is characterized by two seasons, a mild, wet winter and a hot, dry summer. In recent years, many areas have become vulnerable to the impact of extreme climate events. The impact of these events on water supplies has become more pronounced. This study states that there is a tangible impact of extreme climate events upon both water resources quality and water supplies. The Nile river water turbidity was investigated as an operational indicator for the water treatment plants (WTPs). The results illustrated that an unprecedented increase in average turbidity of raw water in Upper Egypt (from 4 up to 110 NTU) led to a cut in water supplies for up to 100 hours in some areas. While in Alexandria the turbidity did affect WTP operation efficiency, safe water could still be produced. Cuts in water supply would have an impact on hygiene and make people prone to use unsafe water sources. These consequences stimulate water supply bodies to develop action plans to mitigate and/or avoid such potential impacts on public health. This study suggests proposed steps to develop an appropriate plan to face such extreme events.

Foodborne and waterborne illness among Canadian Indigenous populations: A scoping review.

Indigenous populations are often at higher risk for foodborne illness than the general Canadian population. To investigate the extent of the literature on the link between food safety and the occurrence of foodborne and waterborne illness in Canadian Indigenous populations. A scoping review was conducted using search strings in five databases and grey literature to identify all papers that studied a Canadian Indigenous population and referred to any potential associations between food safety (including consumption and preparation of traditional foods and retail foods) or water safety practices and food or waterborne illness. Two authors screened papers based on inclusion and exclusion criteria. Included documents were analyzed for emergent themes. From 1,718 unique records identified, 21 documents were selected. Foodborne illness was most common in children up to 14 years old. Walrus, seal, caribou and whale were the most common traditional foods tied to foodborne illness and were primarily associated with botulism and trichinosis. Aside from consuming the food raw, fermentation was the most common traditional preparation method linked to foodborne illness. There was concern about the safety of retail food but no clear link was identified with foodborne illness. Lastly, although there was concern about tap water, the use of alternate water sources, such as untreated brook water, and hygiene and cleaning practices in communities with boil water advisories were the most common risk behaviours associated with waterborne illness. Consumption of certain game meats, as well as the use of traditional fermentation practices may lead to an increased risk of foodborne illness among Indigenous populations. Concern about tap water may lead to use of unsafe alternate water sources. Further research is needed to examine potential culturally appropriate food and water safety opportunities.

A large and persistent outbreak of typhoid fever caused by consuming contaminated water and street-vended beverages: Kampala, Uganda, January \u2013 June 2015

BackgroundOn 6 February 2015, Kampala city authorities alerted the Ugandan Ministry of Health of a “strange disease” that killed one person and sickened dozens. We conducted an epidemiologic investigation to identify the nature of the disease, mode of transmission, and risk factors to inform timely and effective control measures.MethodsWe defined a suspected case as onset of fever (≥37.5 °C) for more than 3 days with abdominal pain, headache, negative malaria test or failed anti-malaria treatment, and at least 2 of the following: diarrhea, nausea or vomiting, constipation, fatigue. A probable case was defined as a suspected case with a positive TUBEX® TF test. A confirmed case had blood culture yielding Salmonella Typhi. We conducted a case-control study to compare exposures of 33 suspected case-patients and 78 controls, and tested water and juice samples.ResultsFrom 17 February–12 June, we identified 10,230 suspected, 1038 probable, and 51 confirmed cases. Approximately 22.58% (7/31) of case-patients and 2.56% (2/78) of controls drank water sold in small plastic bags (ORM-H = 8.90; 95%CI = 1.60–49.00); 54.54% (18/33) of case-patients and 19.23% (15/78) of controls consumed locally-made drinks (ORM-H = 4.60; 95%CI: 1.90–11.00). All isolates were susceptible to ciprofloxacin and ceftriaxone. Water and juice samples exhibited evidence of fecal contamination.ConclusionContaminated water and street-vended beverages were likely vehicles of this outbreak. At our recommendation authorities closed unsafe water sources and supplied safe water to affected areas.

Risks of Domestic Underground Water Sources in Informal Settlement in Kabwe – Zambia

Informal settlements are a hot spot for disaster risks worldwide. They are characterised by limited provision of basic services. Water being a critical life support resource is not adequately provided. Residents usually rely on unsafe water sources of hand dug wells. Pit latrines are a major facility for sanitary purposes. Further, informal settlements high population density residing in poor housing units is a common characteristics. Risks of underground water pollution are high due to the proximity of sanitation facilities to unprotected shallow wells increasing the possibility of feacal contamination by ecoli and coli form. This paper presents a case of Makululu informal settlement in Zambia. A total of 385 respondents were identified at random while purposive sampling identified key informants. Water samples collected from 12 hand dug wells located close to pit latrines were tested for coli form and ecoli. Testing was done before and after the rainy season to analyse the relationship between pit latrines and wells as well as the relationship with rainfall distribution pattern to ascertain levels of risks. Water was tested to determine the levels of contamination based on the presence of ecoli and coli form. Laboratory results indicated that 90 percent of water consumed in Makululu informal settlement is highly contaminated by faecal coliforms.

Evaluating coagulant activity of locally available <i>Syzygium cumini</i>, <i>Artocarpus heterophyllus</i> and <i>Moringa oleifera</i> for treatment of community drinking water, Uganda

Most rural communities in Africa are without access to treated water and therefore use the readily available unsafe water sources exposing them to water borne diseases. This calls for the need for action to search for affordable and simple solutions. This research therefore examined the effectiveness of readily available natural coagulants Syzygium cumini (Javaplum), Artocarpus heterophyllus (Jackfruit) and Moringa oleifera (Moringa) using ‘Jar Test’. Water turbidity and coliforms removal from community drinking water by seeds extracts of natural coagulants was examined. Turbidity removal increased with coagulants concentration in (solvents extracts water and NaCl). Optimal turbidity removal occurred at 40 mg/l coagulant concentration with low and medium turbidity raw water for both solvents extracts and at 60 mg/l for Na Cl extract with high turbidity water. Compared to alum [KAl (SO 4 ) 2 .12(H 2 O)], the turbidity removal effectiveness was: alum> Moringa oleifera > Artocarpus heterophyllus > Syzygium cumini , except for 1MNaCl extract where it was: alum> Artocarpus heterophyllus > Moringa oleifera > Syzygium cumini .Optimal turbidity removal was: Moringa oleifera 97.7%, Artocarpus heterophyllus 95.8% and Syzygium cumini 94.1%. The seed extracts were also effective as water disinfectants (Moringa>Jackfruit>Java plum). The use of Jackfruit and Java plum and Moringa, for water treatment is recommended. © 2015 International Formulae Group. All rights reserved. Keywords: Coagulant activity, Artocarpus heterophyllus , Moringa oleifera , Syzygium cumini , community drinking water treatment, turbidity removal

The role of handpump corrosion in the contamination and failure of rural water supplies

There has been much discussion over many years regarding the origin of elevated iron concentrations in rural water supplies in sub-Saharan Africa and Asia. High iron concentrations are often assumed to be naturally occurring in groundwater, despite several studies over the last 30 years which also point to the role of handpump corrosion in aggressive groundwater. Handpump standards specify that galvanized iron pump materials should not be used in groundwater due to the risk of corrosion, yet this advice is not always followed. High iron concentrations, whether naturally occurring, or present as a result of corrosion, have an impact on taste, odour, and appearance of water and can promote the growth of unpleasant iron metabolizing bacteria. These effects often result in the abandonment of boreholes, sometimes only a year old, and a return to unprotected and unsafe water sources. Where boreholes are not abandoned, the effects of corrosion can cause pump materials to degrade to the point where the pump becom...

Upgrading a Piped Water Supply from Intermittent to Continuous Delivery and Association with Waterborne Illness: A Matched Cohort Study in Urban India

BackgroundIntermittent delivery of piped water can lead to waterborne illness through contamination in the pipelines or during household storage, use of unsafe water sources during intermittencies, and limited water availability for hygiene. We assessed the association between continuous versus intermittent water supply and waterborne diseases, child mortality, and weight for age in Hubli-Dharwad, India.Methods and FindingsWe conducted a matched cohort study with multivariate matching to identify intermittent and continuous supply areas with comparable characteristics in Hubli-Dharwad. We followed 3,922 households in 16 neighborhoods with children <5 y old, with four longitudinal visits over 15 mo (Nov 2010–Feb 2012) to record caregiver-reported health outcomes (diarrhea, highly credible gastrointestinal illness, bloody diarrhea, typhoid fever, cholera, hepatitis, and deaths of children <2 y old) and, at the final visit, to measure weight for age for children <5 y old. We also collected caregiver-reported data on negative control outcomes (cough/cold and scrapes/bruises) to assess potential bias from residual confounding or differential measurement error.Continuous supply had no significant overall association with diarrhea (prevalence ratio [PR] = 0.93, 95% confidence interval [CI]: 0.83–1.04, p = 0.19), bloody diarrhea (PR = 0.78, 95% CI: 0.60–1.01, p = 0.06), or weight-for-age z-scores (Δz = 0.01, 95% CI: −0.07–0.09, p = 0.79) in children <5 y old. In prespecified subgroup analyses by socioeconomic status, children <5 y old in lower-income continuous supply households had 37% lower prevalence of bloody diarrhea (PR = 0.63, 95% CI: 0.46–0.87, p-value for interaction = 0.03) than lower-income intermittent supply households; in higher-income households, there was no significant association between continuous versus intermittent supply and child diarrheal illnesses. Continuous supply areas also had 42% fewer households with ≥1 reported case of typhoid fever (cumulative incidence ratio [CIR] = 0.58, 95% CI: 0.41–0.78, p = 0.001) than intermittent supply areas. There was no significant association with hepatitis, cholera, or mortality of children <2 y old; however, our results were indicative of lower mortality of children <2 y old (CIR = 0.51, 95% CI: 0.22–1.07, p = 0.10) in continuous supply areas. The major limitations of our study were the potential for unmeasured confounding given the observational design and measurement bias from differential reporting of health symptoms given the nonblinded treatment. However, there was no significant difference in the prevalence of the negative control outcomes between study groups that would suggest undetected confounding or measurement bias.ConclusionsContinuous water supply had no significant overall association with diarrheal disease or ponderal growth in children <5 y old in Hubli-Dharwad; this might be due to point-of-use water contamination from continuing household storage and exposure to diarrheagenic pathogens through nonwaterborne routes. Continuous supply was associated with lower prevalence of dysentery in children in low-income households and lower typhoid fever incidence, suggesting that intermittently operated piped water systems are a significant transmission mechanism for Salmonella typhi and dysentery-causing pathogens in this urban population, despite centralized water treatment. Continuous supply was associated with reduced transmission, especially in the poorer higher-risk segments of the population.

Bacteriological Quality in Some Hand-Dug well Water as Source of Drinking Water in Ban Village, Plateau State, Nigeria

Access to potable water and healthy environment has been a concern worldwide. Developing nation like Nigeria has been facing critical challenge in accessing safe drinking water. Therefore, the people still depend on unsafe water sources such as rivers, streams and hand dug wells. This study examined the bacteriological quality of 16 drinking dug well water in four selected communities (Bantin, Tom, Bator and Rek) in Ban village of Plateau state, Nigeria. Four samples from each of the wells were collected from the communities. Biological contaminations were investigated using standard method (Multiple test tube method). The biological contamination rates were higher (110coliforms/100 mL) in Tom and 108 coliforms/100 mL in Bantin followed by 81.27 coliforms/100 mL in Banton and Rek with 67.78 coliforms/100 mL being the least (Tom>Batin>Bator>Rek), all indicated gross pollution. However, the only well that was found to be fit for human consumption was Bator B. The results suggested that the well water contamination in these areas is largely due to faecal contamination. It is recommended that hand-dug well water be treated prior to consumption in order to curtail infection and distance between latrine and dug well should not be less than 30 m.

Cholera outbreaks in Malawi in 1998-2012: social and cultural challenges in prevention and control.

Cholera still remains a significant cause of morbidity and mortality in developing countries, although comprehensive surveillance data to inform policy and strategies are scarce. A desk review of the national cholera database and zonal and districts reports was conducted. Interviews were conducted with district health management teams, health workers, and participants in communities in six districts affected by cholera in 2011/2012 to obtain data on water, sanitation, and sociocultural issues. From 1998 to 2012, cholera outbreaks occurred every year in Malawi, with the highest number of cases and deaths reported in 2001/2002 (33,546 cases, 968 deaths; case fatality rate [CFR] 2.3%). In 2011/2012, cholera outbreak was widespread in the southern region, affecting 10 out of 13 districts, where 1,806 cases and 38 deaths (CFR 2.1%) were reported. Unsafe water sources, lack of maintenance of broken boreholes, frequent breakdown of piped water supply, low coverage of pit latrines (range 40%-60%), lack of hand washing facilities (< 5%), salty borehole water, fishermen staying on Lake Chilwa, cross-border Malawi-Mozambique disease spread, and sociocultural issues were some of the causes of the persistent cholera outbreaks in Malawi. Despite improvements in safe drinking water and sanitation, cholera is still a major public health problem. Introduction of a community-led total sanitation approach, use of social and cultural information in community mobilization strategies, and introduction of an oral cholera vaccine could help to eliminate cholera in Malawi.

Health as a sustainability indicator within water resources management in rural and peri-urban areas of central northern Namibia

In this paper, a modelling approach is presented which is able to analyze a water-supply regime in order to comprehend health-related aspects in water resources management. The area of investigation is the Cuvelai-Etosha Basin in central northern Namibia. Major health hazards for the rural and peri-urban population stem from the usage of unsafe water sources. In the systems analysis, the variable Health turned out to be one of the major sustainability indicators. Furthermore, the identification of cause–effect chains revealed that education is a key factor in improving users’ health situation, whereas poverty significantly degrades it.

Epidemiology of human fascioliasis and intestinal parasitosis among schoolchildren in Lake Tana Basin, northwest Ethiopia

Parasitic diseases are the second most frequent cause of outpatient morbidity in Ethiopia. A cross-sectional study was conducted in Lake Tana Basin, northwest Ethiopia, from November 2007 to February 2008, to assess the magnitude and associated risk factors for parasitic diseases, including human fascioliasis. We examined 520 stool samples from randomly selected schoolchildren in six schools by microscopy. Rapid sedimentation and Kato-Katz techniques were used to detect and count Fasciola and Schistosoma eggs. The formol-ether concentration method was used for the identification of other helminth eggs, larvae and cysts of protozoan parasites. The overall prevalence of intestinal parasitic infections was 71.3% (95% CI 67.3-75.1%). Hookworm was the predominant intestinal parasite (23.5%, 95% CI 19.8-27.1%), followed by Ascaris lumbricoides (18.5%, 95% CI 15.2-21.9%) and Schistosoma mansoni (16.7%, 95% CI 13.5-19.9%). One hundred and sixty-three (31.4%) children had multiple parasitic infections. The most relevant finding was a prevalence of Fasciola spp. of 3.3% in an area where only sporadic cases have been reported previously. The risk of Fasciola spp. infection was significantly associated with raw vegetable consumption, use of unsafe drinking water sources, irrigation practices and sheep and/or cattle ownership. Irrigation practices, male gender, raw vegetable consumption and use of unsafe drinking water sources were risk factors for S. mansoni infection. A high prevalence of parasitic infections among children in the region was found, including a relatively high prevalence of Fasciola spp. infection. Epidemiological studies on the magnitude of parasitic infections in different regions will enable high-risk communities to be identified and allow for planning of appropriate interventions.

Water, Technology, and Development: Transformations of Development Technonatures in Changing Waterscapes

Delivering safe drinking water is often equated with delivering development in much of the Global South. Yet different arrangements of technologies, waters, and social relations constitute uneven waterscapes and produce different water — society relations across sites and scales. Analyzing the contradictory roles of water-producing technologies and differentiated waters in enabling and challenging processes of development thus becomes important to explaining the political ecologies of development. In order to investigate the technonatural relations of power that constitute development, I look at the ways that different types of waters, water technologies, nature (aquifers, groundwater, arsenic), and power relations coproduce water (in)securities and (un)healthy development subjects, with a case study from waterscapes of the Bengal Delta. Contaminated tubewells have resulted in a drinking water crisis and a reconfiguration of hydro — social relations. Groundwater usage for drinking water purposes was introduced via tubewell technology, creating a public health success story as ‘safe’ groundwater offered alternatives to the consumption of unsafe surface water sources that had caused high morbidity and mortality rates. But a situation of millions of tubewells producing water with unsafe levels of naturally occurring arsenic has resulted in challenging such development narratives of success, where the tubewells that embodied social status and notions of progress (producing ‘good water’) came to slowly poison people across the delta (with ‘bad water’). I detail the ways that hybrid waters (safe/unsafe/untested and good/bad) and the discourses of water poisoning are produced by water technologies, aquifers, and social relations that are enrolled to support notions of development; in addition, I critically analyze the ways that development goes awry when these technonatural assemblages are unexpectedly altered by the agencies and materialities of variously contaminated waters, differentiated aquifers, and the changing status of water-producing technologies. In contributing to political — ecological analyses of water and technology, I raise questions about the troubled relationship between development and so-called appropriate technologies by bringing attention to the articulations and mutual enrollments of technologies, ecologies, discourses, and subjects in the technonatural processes of development.

Leech endoparasitism: report of a case and review of the literature

We report the case of an 11-year-old boy who presented with fresh blood in his mouth and a history of sore throat during the past 2 weeks that was unresponsive to antibiotic therapy. Inspection of the oral cavity revealed a black circular mass attached to the posterior wall of the oropharynx. This mass was determined to be a live engorged leech. Leech endoparasitism is caused by aquatic leeches that attach themselves to mucus membranes of body cavities after the host has swum in bodies of fresh water or drunk from unsafe water sources. Pharyngeal hirudiniasis may present in different forms depending on the exact location of the parasite in the body and must be included in the list of differential diagnosis for common conditions such as pharyngitis, hemoptysis or anemia in pediatric patients living in endemic areas.

An assessment of quality of water from boreholes in Bindura District, Zimbabwe

This study assessed the water quality of 144 boreholes in Bindura District in Mashonaland Province of Zimbabwe as part of a borehole rehabilitation project implemented by a local NGO. In previous studies it has been observed that some boreholes are not used for domestic purposes because of consumer perceived poor water quality. Consequently, communities have resorted to unsafe alternative water sources thus creating health risks. The study was carried out in June 2005. The objectives of the study were to assess the levels of parameters associated with the aesthetics of the water and to compare them with guideline values for drinking water. The study also investigated the relationship between some of the measured water quality and the consumer perceived water quality. Measured water quality parameters included pH, temperature, electrical conductivity (EC), turbidity, calcium (Ca), magnesium (Mg) and iron (Fe). All parameters were measured in the field except Ca, Mg and Fe, which were measured in a laboratory using a spectrophotometer. Consumer perceptions on water quality were investigated through interviews with the consumer community. Turbidity was found to be 0.75–428(20.8 ± 59.2; n = 144) NTU, pH 5.7–9.3 (6.88 ± 0.46; n = 144), temperature 18–26.8 (22.6 ± 2.1; n = 144) °C. EC 26–546 (199 ± 116; n = 144) μS/cm, Ca 6–71.6 (26.9 ± 14.1; n = 81) mg/l, Mg 1.2–49.6 (12.3 ± 10.0; n = 81) mg/l and Fe 0.08–9.60 (0.56 ± 1.15; n = 81) mg/l. Some 23% of the samples had pH outside the recommended range of 6.5–8.5, whilst 59% of the samples had turbidity values exceeding the 5NTU WHO limit. For EC, all samples had values less than the WHO derived limit of 1380 μS/cm. All Ca and magnesium values were within the common and recommended levels of 100 mg/l and 70 mg/l respectively. Iron had values greater than the WHO and SAZ limit of 0.3 mg/l in 36% of the samples. Water quality was deemed satisfactory for taste and soap consumption by 95% and 72% of the respondents respectively. Satisfaction was higher for drinking compared to soap consumption meaning that generally hard waters may still be acceptable for drinking purposes. The water quality met the stipulated standard or guideline value from a minimum of 41% (turbidity) to a maximum of 100% (EC, Ca and Mg). There was no correlation between taste and conductivity as some 5% of the respondents suggested the water was unsatisfactory although all EC values were far below the maximum limit. Again there was no correlation between iron and taste as iron had 36% of the samples above the threshold of 0.3 mg/l whilst objectionable taste perception was only in 5% of the cases. It is recommended that priority in future projects should be given to repairs of boreholes whose water quality is acceptable according to consumer perceptions obtained at project planning stage. Low cost household treatment aimed at improving quality should be investigated.

The Drinking Water State Revolving Fund Helps Ground Water Systems Deliver Public Health Protection

The Drinking Water State Revolving Fund Helps Ground Water Systems Deliver Public Health Protection

A Survey of the impact of Guinea worm eradication program in Ohaukwu L.G.A. Ebonyi State, Nigeria

Campaign for the eradication of dracunculiasis (Guinea worm disease) began in Ebonyi State in the 1980s. A combination of interventions consisting of construction of bore holes,chemical treatment of unsafe water sources with temephos, distribution of filters, health education, social mobilization and active surveillance were applied in Ohaukwu L.G.A. from the early 1990s. Records from health workers in the area showed an infection rate of 4.7%(287/6050) in eight villages from 2001 to 2002. We conducted a survey of the impact of the eradication program in the same area from October 2002 to May 2003. The results showed a decrease in the infection rate with 57 cases in the eight villages. Thirty-five of these cases were recurrent while twenty-two had the infection for the first time. About 63.2% of the infected persons did not use the boreholes for various reasons especially due to its salty taste. Most of the people did not filter or boil their drinking water and their reasons include time factor and the exercise being boring. More than half of those infected indicated that they visited the ponds while the worms were emerging from their bodies. Our study also showed that the intensity of health education had declined and the boreholes were not regularly maintained. Renewed awareness and greater participation of the communities and the local government will help free the area from the disease. KEY WORDS: Guinea worm, Eradication, Impact Journal of Biomedical Investigation 2004;2(1): 31-34

The impact of educational videotapes on water contact behaviour of primary school students in the Dongting Lakes region, China.

Multimedia has become increasingly important in educational programmes in schools in all societies, and has potential value for health education. We developed a video and a comic book on the transmission and prevention of schistosomiasis for use in primary schools in endemic areas of China. The material was designed to increase children's knowledge of schistosomiasis as an environmental disease and to encourage them to reduce their contact with unsafe water sources. To test the effectiveness of the video and booklet, a quasi-experimental study was conducted among 1,739 children in 50 primary schools in the Dongting Lake region. A self-administered questionnaire pre- and post-intervention showed a significant increase in knowledge about schistosomiasis in the intervention schools. Significantly, this change was associated with a decrease in contact with unsafe water sources, as established from water contact observations. This behavioural change suggests the value of short, targeted educational interventions to decrease risk of infection.

Where health care has no access: the nomadic populations of sub-Saharan Africa.

Nomadic and seminomadic pastoralists make optimal use of scarce water and pasture in the arid regions south of the Sahara desert, spreading from Mauretania in the west to Somalia in East Africa. We attempted to summarize the fragmentary evidence from the literature on the health status of these populations and to assess the best ways to provide them with modern health care. Infant mortality is higher among nomadic than among neighbouring settled populations, but childhood malnutrition is less frequent. Nomads often avoid exposure to infectious agents by moving away from epidemics such as measles. Trachoma is highly prevalent due to flies attracted by cattle. The high prevalence of tuberculosis is ascribed to the presence of cattle, crowded sleeping quarters and lack of health care; treatment compliance is generally poor. Guinea worm disease is common due to unsafe water sources. Helminth infections are relatively rare as people leave their waste behind when they move. Malaria is usually epidemic, leading to high mortality. Sexually transmitted diseases spread easily due to lack of treatment. Leishmaniasis and onchocerciasis are encountered; brucellosis occurs but most often goes undetected. Drought forces nomads to concentrate near water sources or even into relief camps, with often disastrous consequences for their health. Existing health care systems are in the hands of settled populations and rarely have access to nomads due to cultural, political and economic obstacles. A primary health care system based on nomadic community health workers is outlined and an example of a successful tuberculosis control project is described. Nomadic populations are open to modern health care on the condition that this is not an instrument to control them but something they can control themselves.

Dracunculiasis in Cameroon at the threshold of elimination.

Dracunculiasis is endemic in Mayo Sava Division in the Far North Province of Cameroon. Transmission occurs during the rainy season with a peak in the months of July and August. A combination of interventions consisting of active surveillance, social mobilization, health education, distribution of filters, construction of new water sources, chemical treatment of unsafe water sources with temephos, and case containment were applied in Mayo Sava in 1990-1995 by the national Guinea Worm Elimination Programme (GWEP). Dracunculiasis cases were detected by village health workers, confirmed by health outreach teams and reported weekly to the GWEP. A decline in the incidence of dracunculiasis by 98.1% from 778 cases in 1990 to 15 in 1995, and in the number of endemic villages by 92.7% from 82 in 1990 to 6 in 1995 was achieved. The proportion of cases identified < or =24 hours of worm emergence increased from 19% in 1991 to 73.6% in 1993. Over 1500 nylon monofilament filters were distributed yearly to endemic villages lacking safe drinking water sources, while 81 new water sources were constructed (boreholes, wells and dikes), 55% in 1992-1993. The success of GWEP is attributed mainly to: intensive and simultaneous implementation of interventions in highly endemic villages in the first 3 years of the programme, case containment, and cash reward. Cameroon is on the threshold of eliminating dracunculiasis from Mayo Sava but the major remaining obstacle is the ever increasing threat of re-infestation from neighbouring countries.